Improve progress indicator

Running axe puts dots in the command line to show a test was completed, or a comma to show it was skipped. That sort of works, but it isn't great. We can do much better.

Start by running axe and inspecting the command-line progress output that uses dots for completed tests and commas for skipped tests. The issue does not name files, tests, or a desired replacement, so the target behavior and completion criteria need to be agreed before implementation.

Written by the indexing model from the issue text.